L3281 STMicroelectronics, L3281 Datasheet
L3281
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L3281 Summary of contents
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... MICROPHONE SUITABLE FOR DYNAMIC EARPHONE AND DYNAMIC OR ELECTRET MICROPHONE AGC CONTROL ON BOTH SENDING AND RECEIVING DESCRIPTION The L3281 is an electronic speech circuit devel- oped to replace hybrid circuits in telephone sets that can be operated in parallel with other phones. BLOCK DIAGRAM June 1993 This is advanced information on a new product now in development or undergoing evaluation. Details are subject to change without notice. ...
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... L3281 PIN CONNECTION (top view) ABSOLUTE MAXIMUM RATINGS Symbol V Line Voltage (3 ms pulse Line Current L P Total Power Dissipation, T tot T Operating Temperature op T Junction Temperature j THERMAL DATA Symbol R Thermal Resistance Junction Ambient Max th j-amb 2/10 Parameter = 55 C amb Parameter Value Unit ...
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... TEST CIRCUITS Figure 1. Figure 2. Figure 3. L3281 3/10 ...
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... L3281 ELECTRICAL CHARACTERISTICS 1kHz; Unless Otherwise Specified Symbol Parameter V Line Voltage l CMRR Common Mode Rej. Ratio G Sending Gain tx DG Delta Sending Gain tx THD Sending Distortion tx N Sending Noise tx Z Mic. Input Impedance ml G Receiving Gain rx DG Delta Receiving Gain ...
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... DTMF LOW ACTIVE TO LINE (DIAL) OUTPUT OPEN ACTIVE TO LINE (SPEECH) OUTPUT CIRCUIT DESCRIPTION TWO TO FOUR WIRE CONVERSION The L3281AB is based on a Wheastone bridge configuration. To balance the bridge the following relation must be satisfied Figure 4: 2/4 Wire Conversion BEEP ACTIVE TO EARPHONE OUTPUT ...
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... L3281 DC CHARACTERISTIC The fig.5 shows the equivalent simplified circuit of the DC regulator that provides to give the oppor- tune DC impedance Zdc. Idc Idc since Idc Z4 2 When and considering neglectible the VD + VR1 variation versus line current : VL ZDC ...
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... The AGC function of the voltage at pin 14 and decreases the gain when the line current increases (5.5dB to 6.0dB). The final stage is a single ended amplifier with low output impedance optimized to drive mag- netic/dynamic transducers. L3281 7/10 ...
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... L3281 DIP14 PACKAGE MECHANICAL DATA DIM. MIN. a1 0. 1.27 8/10 mm TYP. MAX. 1.65 0.5 0.25 20 8.5 2.54 15.24 7.1 5.1 3.3 2.54 inch MIN. TYP. MAX. 0.020 0.055 0.065 0.020 0.010 0.787 0.335 0.100 0.600 0.280 0.201 0.130 0.050 0.100 ...
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... SO14 PACKAGE MECHANICAL DATA DIM. MIN 0 0. 8. 3 TYP. MAX. 1.75 0.2 0.004 1.6 0.46 0.014 0.25 0.007 0.5 45 (typ.) 8.75 0.336 6.2 0.228 1.27 7.62 4.0 1.27 0.020 0.68 8 (max.) inch MIN. TYP. MAX. 0.069 0.008 0.063 0.018 0.010 0.020 0.344 0.244 0.050 0.300 0.15 0.157 0.050 0.027 L3281 9/10 ...
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... L3281 Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specifications mentioned in this publication are subject to change without notice ...